|Geometrische Repräsentation - Element|
|Geometric Representation Item|
|Item de représentation géométrique|
An IfcGeometricRepresentationItem is the common supertype of all geometric items used within a representation. It is positioned within a geometric coordinate system, directly or indirectly through intervening items.
NOTE Definition according to ISO/CD 10303-42:1992
An geometric representation item is a representation item that has the additional meaning of having geometric position or orientation or both. This meaning is present by virtue of:
- being a Cartesian point or a direction
- referencing directly a Cartesian point or direction
- referencing indirectly a Cartesian point or direction
An indirect reference to a Cartesian point or direction means that a given geometric item references the Cartesian point or direction through one or more intervening geometry or topology items.EXAMPLE 1 Consider a circle. It gains its geometric position and orientation by virtue of a reference to axis2_placement (IfcAxis2Placement) that is turn references a cartesian_point (IfcCartesianPoint) and several directions (IfcDirection).EXAMPLE 2 Consider a manifold brep. A manifold_solid_brep (IfcManifoldSolidBrep) is a geometric_representation_item (IfcGeometricRepresentationItem) that through several layers of topological_representation_item's (IfcTopologicalRepresentationItem) references poly loops (IfcPolyLoop). Through additional intervening entities poly loops reference cartesian_point's (IfcCartesianPoint).
NOTE Entity adapted from geometric_representation_item defined in ISO 10303-42.
HISTORY New entity in IFC1.5
|S[0:1]||Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.||X|
|S[0:1]||Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.||X|
<xs:element name="IfcGeometricRepresentationItem" type="ifc:IfcGeometricRepresentationItem" abstract="true" substitutionGroup="ifc:IfcRepresentationItem" nillable="true"/>
<xs:complexType name="IfcGeometricRepresentationItem" abstract="true">
ABSTRACT SUPERTYPE OF(ONEOF(IfcAnnotationFillArea, IfcBooleanResult, IfcBoundingBox, IfcCartesianPointList, IfcCartesianTransformationOperator, IfcCompositeCurveSegment, IfcCsgPrimitive3D, IfcCurve, IfcDirection, IfcFaceBasedSurfaceModel, IfcFillAreaStyleHatching, IfcFillAreaStyleTiles, IfcGeometricSet, IfcHalfSpaceSolid, IfcLightSource, IfcPlacement, IfcPlanarExtent, IfcPoint, IfcSectionedSpine, IfcShellBasedSurfaceModel, IfcSolidModel, IfcSurface, IfcTessellatedItem, IfcTextLiteral, IfcVector))
SUBTYPE OF (IfcRepresentationItem);
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